Steps to reproduce

1. Edit a tour http://localhost:8080/magnoliaAuthor/.magnolia/admincentral#app:tours:detail;/magnolia-travels/Vietnam--Tradition-and-Today:edit
2. In the Tour Types multifield, click Select new. The chooser is opened.
3. Open Tour categories in another browser tab http://localhost:8080/magnoliaAuthor/.magnolia/admincentral#app:tourCategories:browser;/tour-types/cultural::
4. Delete an item which is visible in the chooser is the other browser tab
5. Go back to the first tab with the page chooser

Expected results

As author, I don't have to see the changes by other authors when chooser is opened. It's OK if I get new data as soon I open the  chooser again.

Moreover observation actions are unregistered after closing the chooser or even better choosers doesn't need an auto refresh mechanism to improve performance.

Actual results

The change is immediately visible in the chooser.

Moreover observation actions are not unregistered after closing the chooser but are accumulating.

This is not so harmful but also completely useless.

Workaround

Usually not needed but closing the app cleans up.

Development notes

We probably need to bind instance of the observation (preferable no-op = no auto refreshes of the chooser), same way as we bind a dedicated ValueContext for the chooser.